1. Technical Field
The present invention relates to a head-up display device capable of projecting a virtual image on a projection area of a windshield of a vehicle, and allowing the projected virtual image and a foreground of the vehicle to be superimposed and visually recognized through the windshield from an eye point of the vehicle.
2. Background Art
In recent years, with increased and diversified information required by a driver for driving, vehicles such as automobiles or trains employ head-up display devices (HUDs) that display a virtual image of information to be notified the driver of such as information high in the degree of urgency on a windshield of a vehicle, and allow the virtual image and a foreground of the vehicle to be visually recognized through the windshield in a superimposed manner.
As illustrated in FIG. 7, a head-up display device includes an indicator 1 for emitting a display light L, a casing 2 onto which the display light L is incident from the indicator 1, reflective plates 4 and 5 received in the casing 2 to reflect the display light L incident in the casing 2 and then guide it to an opening (not illustrated) provided in the casing 2, and a transparent plate (not illustrated) covering the opening 3 (see JP-A-2008-55940 and JP-A-2010-15037).